I'm very new to ASA. I would like to develop an application for my company, it's production company so it requires to have BOM. Let's say I have a table which recursive relationship as follow.

bom_master

item_id

qty

parent_item_id

Just like usual table structure found on the internet, for the parent item, it's parent_item_id contains null.
My question is that how to query one single parent item with all it's child (no matter how many level will be) at once? Do I need a stored procedure or this can be done using plain SQL statement? Please give me some samples or hits.